Laser welding is currently used to carry out robotic welding. Japanese Patent No. 3229834 discloses an example of such a welding technique, wherein a laser welding apparatus is installed at a tip of a robotic arm for irradiating a laser beam. The laser welding apparatus is configured to move away from a welding point and rotate a reflecting mirror located within the laser welding apparatus, thereby irradiating the laser beam at a predetermined welding point. Such type of welding is referred to as remote welding.
However, in laser welding, a gas with eluted metal is produced from a portion of a work piece irradiated by the laser beam. Such a gas is referred to as a fume. In particular, when irradiating the laser beam at the work piece, an anti-corrosive agent (e.g., Zn) coated over the work piece (e.g., a steel sheet) is plasmarized to produce an ion. Such an ion is then cooled so as to form a particulate after floating in air. This particulate becomes somewhat of a cloud-like matter that blocks the laser beam. Such a fume needs to be removed since it destabilizes the amount of heat that the laser beam applies to the work piece.
In conventional laser welding or processing such as that disclosed in Japanese Laid-Open Patent Publication No. 2004-1043, a device for generating airflow over the work piece is installed in order to remove the fume from around the work piece.